1. Field of the Invention
The present invention relates to a tubular member construction which has flexibility and is provided with ring-shaped or spiral-shaped corrugations on the peripheral wall of a tubular member.
2. Description of Related Art
A metallic band member having a flat plate shape is turned so as to be wound into a spiral shape, and a lower edge portion and an upper edge portion of the band member are lapped on each other, by which a tubular member that is long in one direction can be formed. If spiral-shaped corrugations as shown in FIG. 12 are formed on the peripheral wall of the tubular member thus formed (see FIG. 2C), or if ring-shaped corrugations are formed continuously in the axial direction of the tubular member, the tubular member can be provided with flexibility as known well. This tubular member 1 having flexibility can be formed by using one or a plurality of band members.
Such a flexible pipe 1 is used in various applications; for example, it is used to cover the peripheral portion of an electrical harness or a pipe for a vehicle. That is, the flexible pipe 1 is used as a protective material for preventing these elements from being damaged by the interference with a vehicular structural member.
The flexible pipe 1 maintains its shape due to the characteristics of the metal itself. However, for example, in the case where the flexible pipe 1 is used in a vibrating portion, as the pipe is repeatedly subjected to bending deformation, or in some applications of the flexible pipe 1, looseness 1a is produced at the end of the flexible pipe 1 as shown in FIG. 13. Especially when the flexible pipe 1 is formed by overlapping two or more band members inside and outside, the flexible pipe 1 is liable to come loose as compared with the flexible pipe 1 formed by one band member. In addition to this, when the band member is formed by different types of metals and used in a hot portion, the flexible pipe 1 is much liable to come loose due to a difference in thermal expansion between the inside layer material and the outside layer material.
To prevent the looseness, the overlapped portion of band members of the flexible pipe 1 is bonded with an adhesive. Also, it is conceivable that the looseness can be prevented by putting a cap at the end of the flexible pipe 1.
However, if the flexible pipe is bonded with an adhesive, the flexibility of the flexible pipe is lost by the hardness of the adhesive. Further, in the case where the flexible pipe is disposed in a hot portion, the adhesive is sometimes denatured by heat so that the adhesive strength is lost, which results in a high manufacturing cost.
If a cap is put at the end of the flexible pipe, in this case as well, if the flexible pipe is disposed in a hot portion, the material is restricted and becomes expensive. In the case where the cap is disposed in a vibrating portion, the cap may come off unless an adhesive is used.
Also, when a vehicular harness, pipe, or the like has already been connected to the vehicle and is not detachable, in some cases, a split pipe (see FIG. 7) is formed by splitting the flexible pipe, and the flexible pipe is mounted around the harness etc. via a split after the harness etc. have been connected. In this case as well, there arises a problem in that the split edge portion comes loose when an attempt is made to widen the split in order to mount the split pipe on the harness.
The present invention has been made in view of the above situation, and accordingly an object thereof is to provide a tubular member construction capable of preventing the end portion or edge portion of a flexible pipe from coming loose without costing.
To achieve the above object, the present invention provides a tubular member construction in which a tubular member is formed by winding a metallic band material in a spiral shape in an overlapped manner, and a plurality of wavy corrugations are formed in the peripheral wall portion of the tubular member in the axial direction of the tubular member, wherein the corrugations located in an opening end portion of the tubular member are pressed and collapsed to form a collapsed portion so as to prevent the band material located in the opening end portion from coming loose.
Also, to achieve the above object, the present invention provides a tubular member construction in which a tubular member is formed by winding a metallic band material in a spiral shape in an overlapped manner, and a plurality of wavy corrugations are formed in the peripheral wall portion of the tubular member in the axial direction of the tubular member, wherein slit edge portions are formed by one split formed in the range from one opening end portion to the other opening end portion of the tubular member, and the corrugations located in the split edge portions are pressed and collapsed to form a collapsed portion so as to prevent the band material located in the split edge portion from coming loose.
The above-mentioned tubular member can be constructed as described below.
The tubular member can be made flexible. Also, by using two or more of the metallic band materials, the band materials can be overlapped with each other inside and outside to form a tubular member of two or more layers.
The two or more band members can be formed of two or more different types of metals. Further, two of the band materials can be used, and an inside layer material of the tubular member can be formed of stainless steel or a stainless steel alloy and an outside layer material thereof can be formed of aluminum or an aluminum alloy.
Also, the collapsed portion of the tubular member can be formed in a plurality of locations at intervals.
The tubular member can be manufactured by inserting the corrugations of the tubular member between a gear and a dolly block, which are disposed with a predetermined gap provided therebetween, and by pressing teeth of the gear against the corrugations while the gear is rotated to form the collapsed portions.
Further, the tubular member can be mounted at the outer periphery of an exhaust gas recirculation (EGR) pipe for connecting an intake pipe connected to a combustion air intake port of an automobile engine to an exhaust pipe connected to a combustion gas exhaust port of the engine.
Also, the tubular member can be flexible, and the tubular member can be mounted around at least one of exhaust pipes connected to both ends of a catalytic converter provided on the combustion gas exhaust port side of an engine.